Answer:
The value of x is 3. The length of PQ, QR and PR are 55.
Explanation:
Given that the lengths in an equilateral triangle are all the same. We can assume that PQ = QR = PR. So we can choose any 2 lengths and compare it :
![PQ = QR](https://img.qammunity.org/2021/formulas/mathematics/high-school/4h03znq1om53r401e9ecgsnz0wzzxbcu2e.png)
![18x + 1 = 24x - 17](https://img.qammunity.org/2021/formulas/mathematics/high-school/5zwthkl76rvn4timb8fwi1ymahuc4261s6.png)
![1 + 17 = 24x - 18x](https://img.qammunity.org/2021/formulas/mathematics/high-school/z6amm9j1iq11e1gehqbfzyc841b4yfpb1q.png)
![6x = 18](https://img.qammunity.org/2021/formulas/mathematics/high-school/mjsezmldvyza6m22njeydn2pqy0senmfqy.png)
![x = 18 / 6](https://img.qammunity.org/2021/formulas/mathematics/high-school/upqajsspdboyjbxp5989k1eay0ioivnj0r.png)
![x = 3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/k9g036hm5izcxawfiueilvprjv2215oq3t.png)
Next, we have to substitute x = 3 into the expressions :
![PQ = 18(3) + 1 = 55](https://img.qammunity.org/2021/formulas/mathematics/high-school/nbx1ye4hwm1hajbrzfaxi914igctd571v0.png)
![QR = 24(3) - 17 = 55](https://img.qammunity.org/2021/formulas/mathematics/high-school/uos8oxsauut9vtxqiwej4rz4mt31kd2kbq.png)
![PR = 15(3) + 10 = 55](https://img.qammunity.org/2021/formulas/mathematics/high-school/27z1zkoggniu34bg1qe7ft16gj63ozejjd.png)